Method and crimping tool for permanently joining together two sheet metal members

ABSTRACT

A method of permanently joining two sheet material members by placing them in an overlapping position, and simultaneously punching out a portion of each sheet member so that a portion of an uppermost sheet member is disposed in the lowermost sheet member, and said portion of the lowermost sheet member is punched out of the lowermost sheet member to a position offset therefrom, and wherein each of said portions is joined to its respective sheet member by at least a pair of locking tabs. The crimping tool of the invention includes a die means mounted on a frame member and having a first punch tool movably mounted therein. A power operated second punch tool is movably mounted on said frame member for operation with said first punch member to simultaneously punch a portion from an uppermost sheet member into an underlying lowermost sheet member and a portion from said lowermost sheet member to a position offset therefrom, and wherein each of said portions is joined to its respective sheet member by at least a pair of locking tabs.

United States Patent [191 DuVernay 1 Nov. 18,1975

[ METHOD AND CRIMPING TOOL FOR PERMANENTLY JOINING TOGETHER TWO SHEETMETAL MEMBERS [75] Inventor: Arthur C. DuVernay, Algonac,

Mich.

[73] Assignee: Auto-Craft T001 & Die Company, Algonac, Mich.

[22] .Filed: July 26, 1974 [21] Appl. No.: 492,155

UNITED STATES PATENTS 2,254.558 9/1941 Williams ll3/l 16 FF 2.626.687l/l953 Williams v ll3/l 16 FF 2,671,361 3/1954 Sandberg.... ll3/l 16 FF3,599.318 8/l97l Behlen ll3/l N 3,726.000 4/1973 Hafner ll3/l 16 FFPrimary Examiner-C. W. Lanham Attorney, Agent, or Firm-Robert G. Mentag[57] ABSTRACT A method of permanently joining two sheet material membersby placing them in an overlapping position, and simultaneously punchingout a portion of each sheet member so that a portion of an uppermostsheet member is disposed in the lowermost sheet member, and said portionof the lowermost sheet member is punched out of the lowermost sheetmember to a position offset therefrom, and wherein each of said portionsis joined to its respective sheet member by at least a pair of lockingtabs. The crimping tool of the invention includes a die means mounted ona frame member and having a first punch tool movably mounted therein. Apower operated second punch tool is movably mounted on said frame memberfor operation with said first punch member to simultaneously punch aportion from an uppermost sheet member into an underlying lowermostsheet member and a portion from said lowermost sheet member to aposition offset therefrom, and wherein each of said portions is joinedto its respective sheet member by at least a pair of locking tabs.

5 Claims, 10 Drawing Figures US. Patent Nov. 18,1975 Sheet 1 of4 U.S.Patent Nov. 18, 1975 Sheet20f4 3,919,955

U.S. Patent Nov. 18, 1975 Sheet 3 of4 METHOD AND CRIMPING TOOL FORPERMANENTLY JOINING TOGETHER TWO SHEET METAL MEMBERS SUMMARY OF THEINVENTION This invention relates generally to the crimping art, and moreparticularly to a novel and improved method and crimping tool forpermanently joining together two sheets of material.

Heretofore, in order to permanently join two sheets of the same type ofmetal it was necessary to use some form of welding, as, for example,spot welding. However, spot welding does not solve the problem ofpermanently joining two dissimilar materials together, as, for example,sheet metal and aluminum.

In view of the foregoing, it is an important object of this invention toprovide a method and means for permanently joining two sheet memberstogether, regardless of the material from which they are made.

It is another object of the present invention to provide a method ofpermanently joining two sheet material members together by a mechanicalconnection or clinching structure.

It is still another object of the present invention to provide acrimping tool for fastening at least two sheets of material togetherwhich includes a frame member, die means having a workpiece supportingstation for supporting at least two overlapping sheets of materialthereon, a first punch tool mounted in said die means and being normallybiased against the lowermost sheet of material mounted on said diemeans, and being movable a predetermined distance away from the lowermost sheet of material during a crimping operation, a second punch toolmovably mounted on said frame member for engagement with the uppermostsheet of material mounted on said die means, and power means mounted onsaid frame member and being operatively connected to said second punchtool for moving the second punch tool against said sheets of material onthe die means and to punch a portion from the uppermost sheet ofmaterial into the lowermost sheet of material for crimping the twosheets of material together.

Other features and advantages of this invention will be apparent fromthe following detailed description, appended claims, and theaccompanying drawings.

BRIEF DESCRIPTIONOF THE DRAWINGS FIG. 1 is a front elevational view of acrimping tool made in accordance with the principles of the presentinvention.

FIG. 2 is a longitudinal, elevational view, partly in section, withparts broken away, of the crimping tool structure illustrated in FIG. 1,taken along the line 2--2 thereof, and looking in the direction of thearrows.

FIG. 3 is an enlarged, horizontal section view of the crimping toolstructure illustrated in FIG. 1, taken along the line 3-3 thereof, andlooking in the direction of the arrows.

FIG. 4 is a fragmentary, horizontal view of the crimping tool structureillustrated in FIG. 2, taken along the line 4-4 thereof, and looking inthe direction of the arrows.

FIG. 5 is an elevational view of the structure illustrated in FIG. 4,taken along the line 55 thereof, and looking in the direction of thearrows.

FIG. 6 is a fragmentary, elevational, section view of the crimping toolof the present invention, and showing the lower end ofthc structureshown in FIG. 2 in an enlarged condition. and with parts broken away.

FIG. 7 is a horizontal view of the structure illustrated in FIG. 6,taken along the line 77 thereof, and showing two pieces of sheet metalcrimped together by the crimping tool of the present invention and inaccordance with the method of the present invention.

FIG. 8 is a view of the joined metal members of FIG. 7, taken along theline 8-8 thereof, and with the two sheet metal members turned to aposition perpendicular to the plane of the drawing.

FIG. 9 is a section view of the two joined metal members of FIG. 7,taken along the line 99 thereof, and with the two sheet metal membersturned 90 to a position perpendicular to the plane of the drawing.

FIG. 10 is a bottom end view of the round crimping punch employed in theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and in particular to FIGS. 1 and 2, the numeral 10 generally designatesa crimping tool frame. As best seen in FIG. 2, the crimping tool frameincludes a plate-like portion, on the front end of which is integrallyformed a U-shaped portion 12 which is narrower than the portion 11, asshown in FIG. 1. Integrally attached to the U-shaped portion 12 is abase portion 13. The plate-like frame portion 11 is provided with anopening 14.

As shown in FIGS. 1 and 2, a suitable fluid eylin'der, generallyindicated by the numeral 15, is fixedly mounted on the frame portion 1l. The fluid cylinder 15 may be of any suitable type, as for example, apneumatic cylinder. The fluid cylinder 15 includes a cylinder or body 16which is enclosed by the usual end closure members 20. A pair ofattachment arms 17 are integrally attached to each of the end closuremembers 20, as by welding. A machine screw 18 is mounted through asuitable hole in each of the attachment arms 17 and is threadablyengaged in a bore 19 in the frame portion 11, for securing the fluidcylinder 15 to the frame portiton 11. The cylinder end closure members21 are fixedly secured on the cylinder 15 in the usual manner, as by aplurality of tie rods 21 and lock nuts 21A.

As best seen in FIG. 2, the fluid cylinder 15 is provided with the usualcylinder rod 22 which has its outer end threadably mounted in a suitablethreaded bore in a punch head or punch carrier 23. The cylinder rod 22is locked to the punch head 23 by a suitable lock nut 24. The punch head23 is further secured to the outer threaded end of the cylinder rod 22by a metal locking member 28 which is mounted in the inner end of athreaded bore 26 in the punch head 23, and against the threaded end ofthe cylinder rod 22. A locking screw 25 is threadably mounted into thebore 26 for forcing the locking member 28 against the threaded end ofthe cylinder rod 22.

As shown in FIGS. 2 and 3, the punch head 23 is slidably mounted on thefront surface 27 of the frame portion 11 for sliding movement betweenthe solid line crimping position shown in FIG. 2 and the raisedinoperative broken line position designated by the numeral 23a in FIG.2.

As shown in FIG. 3, the punch head 23 is slidably mounted between tworetaianer members 29, each of which is provided with an inwardlyextended shoulder 36 that extends over a mating flange 37 along theadjacent side of the punch head 23, for sliding engagement thereof. Eachof the retainer members 29 is fixed to the frame portion ll by a pair ofmachine screws 30 and a pair of dowel pins 31. Each of the machinescrews 30 extends down through a suitable bore 32, through therespective retainer member 29 and into threaded engagement with athreaded bore 33 in the frame portion 11. The dowel pins 31 are eachoperatively mounted in a dowel hole 29 in the retainer members 29 and inan aligned dowel hole 35 formed in the frame portion 11.

As shown in FIGS. 1 and 2, a U-shaped retainer plate 42 is seated in atransverse slot 43 adjacent the cylinder rod end of the fluid cylinder15. The front attachment arms 17 abut the U-shaped retainer plate 42.The U- shaped retainer plate 42 is held between the front attachmentarms 17 and an abutment plate 38. The abutment plate 38 is secured tothe frame portion 11 by a pair of machine screws 39 which are mounted ina pair of bores 40 in the frame portion 11 and which are threadablyengaged in a pair of threaded bores 41 in the abutment plate 38.

As shown in FIGS. 2 and 6, a backing plate 44 is carried on the lowerface of the punch head 23. A retainer plate 45 is mounted on the lowerface of the backing plate 44. The backing plate 44 and the retainerplate 45 are secured as a unit to the lower face of the punch head 23 bya pair of machine screws 46 and a pair of dowel pins 47. As shown inFIGS. 2 and 6, the retainer plate 45 carries an elongated cylindricalpunch tool 49 which is slidably mounted through a bore 48 formed throughthe retainer plate 45. The punch tool 49 is provided with a head 52 thatis seated in an annular recess 53 formed in the upper face of theretainer plate 45. The punch tool 49 is disposed on an axis which isparallel to the axis of the cylinder rod 22, but which is offset in adirection outwardly from the front face 27 of the frame portion 1B. Thepunch tool 49 is slidably mounted through a bore 51 formed axiallythrough a cylindrical member which is made from a suitable resilientmaterial as, for example, a block of urethane. The resilient member 50is secured to the outer face of the retainer plate 45 by any suitablemeans, as by a suitable adhesive.

The numeral 54 in FIGS. 4 and 6 generally designates the die meansemployed in the invention. The die means 54 is seated in a recess 55that is formed on the upper side of the frame portion 13. A retainerplate 57 is seated in the recess 55 and abuts the inner end wall 56 ofthe recess 55. As shown in FIG. 4, the retainer plate 57 is fixed inplace by a plurality ofsuitable machine screws 58 and dowel pins 59. Asshown in FIGS. 4 and 6, the retainer plate 57 is provided with anintegral, upward extension 62 which is aligned with the resilient member50 and which is provided with a half round bore 63.

As best seen in FIGS. 4 and 6, the retainer plate 57 is provided with anannular recess 64 in the lower face thereof for the reception of thehead 80 of a cylindrical die tool indicated by the numeral '78. The dietool 78 is provided with a cylindrical body portion 79 which extendsupwardly through a bore 76 in the retainer plate 57 and into slidingengagement with the half round bore 63. A movable retainer plate 67 isslidably mounted on the upper surface 66 of the retainer plate 57 and isprovided on the front end thereof with a half round bore 68 which isdisposed in a complementary posititon with the half round bore 63 toform a complete bore for slidable engagement with the tool body 79.

As shown in FIGS. 4 and 5, the movable retainer plate 67 is providedwith a shoulder 70 along each side thereof. The retainer plate 67 issecured in a slidable condition on the retainer plate 57 by a pair ofretainer bars 71 and each has an inwaradly extended flange 69 thatslidably engages one of the shoulders '74 on the retainer plate 67. Theretainer bars 71 are secured in place on the retainer plate 57 by aplurality of suitable machine screws 72 and dowel pins 73. The machinescrews 72 are threadably mounted in threaded bores 74 on the retainerplate 57. The dowel pins 73 extend through the retainer bars '71 andinto operative engagement in dowel holes 75 in the retainer plate 57.

As best seen in FIG. 6, the annular recess 64 in the retainer plate 57has a depth larger than the thickness of the head on the punch tool 78to permit axial movement of the punch tool 78. As shown in FEG. 6, thepunch tool 78 is in the depressed position which it attains when thepunch tool 49 has reached the end of its punching travel or has bottomedout. The punch tool 78 is normally biased upwardly into an inoperativeposition before the punching operation by the following described means.

As shown in FIG. 6, the punch tool spring means includes a cylindrical,tubular member 81 which functions as a spring carrier and which isthreadably mounted in a bore 82 which is formed in the frame por tion13. The bore 82 is axially aligned with the punch tools 49 and 78. Asviewed in FIG. 6, the lower end of the spring carrier 81; is closed, anda coil spring 77 is operatively mounted in the carrier 81, through theopen upper end thereof. The spring 77 normally biases upwardly aninverted T-s'naped pressure finger or pin 83 which is slidably mountedthrough a bore 84 so as to engage the lower end of the punch tool head80 for maintaining a normal, upward spring bias on the punch tool 78.

As shown in FIGS. 2 and 4, the movable retainer plate 67 is held inplace against the retainer plate portion 62 by a resilient cushionmember 85 which is shown as being rectangular and as being made from ablock of urethane. The cushion member 85 is in turn held in position bya retainer block 86 that is secured to the retainer plate 57 by a pairof suitable machine screws 87 (FIG. 4). A guide dowel pin 39 has one endfixedly mounted, as by a press fit, in a bore 99 in the retainer block86, in a position perpendicular to the axis of the punch tools 49 and78. The dowel pin 89 extends into an axial bore 87 formed through thecushion member 85. As described more fuliy hereinafter, the movableretainer plate 67 is movable to the right, as viewed in FIG. 2, during acrimping operation. The cushion member 85 resists such movement of there tainer plate 67 and the dowel pin 89 also functions as a positiivestop to limit the movement of the retainer plate 67.

As shown in FIG. it), the iower end 91 of the punch tool 49 is providedwith a pair of oppositeiy disposed notches 92. The numerals 94 and 95 inFIG. 6 desig nate two pieces of similar or dissimilar sheets of metalthat are being joined by the crimping structure shown in FIG. 6, and inaccordance with the method of the present invention. As shown in FIG. 3,the upper ends of the retainer extension 62 and the retainer plate 63are provided with notches or washed out portions 93 that complement thenotches 92 on the lower end of the punch tool 49 to permit the metalfrom the two sheets of metal 94 and 95 to flow outwardly from under thepunch tool 49 during a crimping operation. The notches 92 on the lowerend of the punch tool 49, and the cut-out portions 93 of the retainerplate portion 62 and the retainer plate 67 are concave, as viewed inFIGS. and 4 respectively.

The crimping tool of the present invention is adapted to crimp ormechanically join two of the same or of different types of metal intoone united part, and it provides the same results as spot welding. Thecrimping tool of the present invention may be used for joiningpermanently a sheet of steel metal with a sheet of aluminum.

In use, the fluid cylinder is operated by fluid under pressure admittedthrough port 100 to move the punch tool 49 upwardly, into a positionwhere the punch carrier 23 is moved to the raised position 23a in FIG.2. A pair of sheet metal members as 94 and 95 would then be disposed ontop of the retainer plate members 62 and 67 in an overlapping condition,as shown in FIG. 6. The fluid cylinder 15 is then operated by fluidunder pressure admitted through port 101 so as to move the punch tool 49downwardly into engagement with the upper metal sheet 94. The punch 94continues to move downwardly until it is in the position shown in FIG.6, wherein the lower punch tool member 78 has been moved downwardly tothe position shown in FIG. 6, so

as to bottom out the complete die portion of the crimping tool. When thepunch tool 49 moves into the engagement with the sheet metal members 94and 95, the resilient member 50 functions as a holding member, since itwill abut the sheet metal members 94 and 95 in its free state before itis compressed to the position shown in FIG. 6. The punch tool 49 punchesa metal portion 96 from the sheet metal member 95 downwardly against thelower tool 78, and a metal portion 97 from the sheet metal member 94downwardly on top of the metal portion 96. The punch tool 49 does notpunch out the sheet metal portions 96 and 97 from their respective sheetmetal members, but moves them downwardly to a position where they arecrimped together, and yet still connectedto their respective sheet metalmembers. When the punch tool 49 bottoms out, the metal within thenotches 92 on the punch tool 49 and the washed-out portions 93 on theretainer plate members 62 and 67 will flow sidewardly from under thepunch tool 49 to form the locking tabs 99. Simultaneously, there is aslight movement of the retainer plate 67 against the resilient block 85to compress the same, and to permit sideward expansion of the metalforming the locking tabs 99. There is also a slight expansion of thepressed-out metal portions 96 and 97 in the opposite or perpendiculardirection, so as to form slightly curved projections or tabs 98.

Experience has shown that the method of the present invention is anexonomical and efficient method for fastening together similar ordissimilar metalsheets. There are no mechanical leverages employed inthe crimping tool structure of the present invention, and it is light inweight, and it can be used as a portable unit for use in a small,confined area. The crimping tool of the present invention is easy tohandle, and the fastening operation is accomplished in one stroke, andwithout any requirement for separate fastening materials. The mechanicalfastening method of the present invention is also carried out withoutdistorting the two sheets of metal which are being joined.

It will be seen that the method of the present invention comprises thefastening together of two sheets of metal by punching a portion from onemetal sheet into a second metal sheet and simultaneously punching out aportion of the second metal sheet, and spreading at least two connectingtabs of metal sidewardly during the punching operation to provide amechanical bond or crimping of the metal to one sheet member to theother sheet member.

The depth of the notches 92 at the other ends thereof adjacent theperiphery of the punch tool 49 should be approximately equal to thethickness of the thicker of the two sheets of material to be joined. Thedepth of the relieved or washed-out areas 93 of the retainer plates 62and 67 should also be equal at their inner ends, adjacent the half-bores63 and 68, to the thickness of the thicker of the two sheets of materialto be joined. The depth of the notches 92 are greatest at the peripheryof the punch tool 49 and taper concave inwardly toward the end 91 of thepunch tool 49. The washed-out areas 93 have their greatest depthadjacent the half bores 63 and 68 and taper outwardly and upwardly tothe upper surfaces of the retainer members 62 and 67.

It will be understood that the cross-sectional shape of the punch tools49 and 78 are not limited to a circular shape but could be square,rectangular and so forth, with the notches 92 being provided on twoopposite sides of any such punch tool 49. It will also be understoodthat the crimping tool of the present invention could be employed forfastening together a plurality of sheet members as, for example, threeor four and so forth.

While it will be apparent that the preferred embodiment of the inventionherein disclosed is well calculated to fulfill the objects above stated,it will be appreciated that the invention is susceptible tomodification, variation and change.

What is claimed is:

l. A crimping tool for fastening at least two sheets of materialtogether, comprising:

a. a frame member:

b. die means mounted on said frame member and having a workpiecesupporting station for supporting at least two overlapping sheets ofmaterial thereon including a fixed retainer plate and a movable retainerplate;

. a first cylindrical punch tool mounted in said die means and having anoperative flat end normally biased against the lowermost sheet ofmaterial mounted on said die means, and being movable a predetermineddistance away from the lowermost sheet of material during a crimpingoperation;

(1. a second cylindrical punch tool movably mounted on said frame memberfor engagement with the up permost sheet of material mounted on said diemeans;

power means mounted on said frame member and being connected to saidsecond punch tool for moving the operative end of said second punch toolagainst said sheets of material on the die means and to punch a portionfrom the uppermost sheet of material into the lowermost sheet ofmaterial for crimping the two sheets of material together;

. the operative end of said second punch tool being flat and providedwith a pair of diametrically disposed notches to form a locking tabbetween the uppermost sheet of material and the portion punched fromsaid uppermost sheet of material;

g, said first punch tool being movable in conjunction with the secondpunch tool away from the lowermost sheet of material a distancesubstantially equal to the thickness of the lowermost sheet of materialto allow a portion of the lowermost sheet of material to be punchedtherefrom when the portion of the uppermost sheet of material is punchedinto the lowermost sheet of material;

h. the die means being provided with a pair of diametrically disposedrelieved areas which are aligned with the notches on the second punchtool and which are operative to form a locking tab between the lowermostsheet of material and the portion punched therefrom;

. said first punch tool being normally biased against the lowermostsheet of material by a spring means; and,

j. the movable retainer plate of said die means being movableperpendicularly to the line of punching force during a punchingoperation to permit the portion of the material being punched out fromthe two sheets of material to flow laterally outward.

2. A crimping tool as defined in claim 1, wherein:

a. said pair of diametrically disposed relieved areas on the die meansare each formed partially on said fixed retainer plate and partially onsaid movable retainer plate.

3. A crimping tool as defined in claim 2, wherein:

a. said fixed retainer plate is substantially L-shaped with one leg ofsaid Lshape being secured to said frame member and having said firstcylindrical punch tool slidably mounted through a bore formed throughsaid one leg of said L-shape, and the other leg of said L-shape beingdisposed longitudinal of said first cylindrical punch tool, and providedwith a longitudinally extended half-round bore through which said firstcylindrical punch tool is slidably mounted; and,

b. said movable retainer plate is movably mounted on said one leg ofsaid fixed retainer plate for movement perpendicular to the longitudinalaxis of the first cylindrical punch tool, and being provided with ahalf-round bore on the end thereof adjacent said fixed retainer platethrough which said first cylindrical punch tool is slidably mounted.

4. A crimping tool as defined in claim 3, including:

a. a stop block fixed on said one leg of said fixed retainer block; and,

b. a resilient cushion member mounted between said movable retainerplate and said retainer block for normally biasing said movable retainerplate against the said fixed retainer plate, and to allow said movableretainer plate to be moved perpendicularly away from the fixed retainerplate during a punching operation.

5. A crimping tool as defined in claim 4, including:

a. a resilient holding member operatively mounted about said secondcylindrical punch tool for engagement with the sheets of material to becrimped for holding the same in place during a punching op-

1. A crimping tool for fastening at least two sheets of materialtogether, comprising: a. a frame member: b. die means mounted on saidframe member and having a workpiece supporting station for supporting atleast two overlapping sheets of material thereon including a fixedretainer plate and a movable retainer plate; c. a first cylindricalpunch tool mounted in said die means and having an operative flat endnormally biased against the lowermost sheet of material mounted on saiddie means, and being movable a predetermined distance away from thelowermost sheet of material during a crimping operation; d. a secondcylindrical punch tool movably mounted on said frame member forengagement with the uppermost sheet of material mounted on said diemeans; e. power means mounted on said frame member and being connectedto said second punch tool for moving the operative end of said secondpunch tool against said sheets of material on the die means and to puncha portion from the uppermost sheet of material into the lowermost sheetof material for crimping the two sheets of material together; f. theoperative end of said second punch tool being flat and provided with apair of diametrically disposed notches to form a locking tab between theuppermost sheet of material and the portion punched from said uppermostsheet of material; g. said first punch tool being movable in conjunctionwith the second punch tool away from the lowermost sheet of material adistance substantially equal to the thickness of the lowermost sheet ofmaterial to allow a portion of the lowermost sheet of material to bepunched therefrom when the portion of the uppermost sheet of material ispunched into the lowermost sheet of material; h. the die means beingprovided with a pair of diametrically disposed relieved areas which arealigned with the notches on the second punch tool and which areoperative to form a locking tab between the lowermost sheet of materialand the portion punched therefrom; i. said first punch tool beingnormally biased against the lowermost sheet of material by a springmeans; and, j. the movable retainer plate of said die means beingmovable perpendicularly to the line of punching force during a punchingoperation to permit the portion of the material being punched out fromthe two sheets of material to flow laterally outward.
 2. A crimping toolas defined in claim 1, wherein: a. said pair of diametrically disposedrelieved areas on the die means are each formed partially on said fixedretainer plate and partially on said movable retainer plate.
 3. Acrimping tool as defined in claim 2, wherein: a. said fixed retainerplate is substantially L-shaped with one leg of said L-shape beingsecured to said frame member and having said first cylindrical punchtool slidably mounted through a bore formed through said one leg of saidL-shape, and the other leg of said L-shape being disposed longitudinalof said first cylindrical punch tool, and provided with a longitudinallyextended half-round bore through which said first cylindrical punch toolis slidably mounted; and, b. said movable retainer plate is movablymounted on said one leg of said fixed retainer plate for movementperpendicular to the longitudinal axis of the first cylindrical punchtool, and being provided with a half-rounD bore on the end thereofadjacent said fixed retainer plate through which said first cylindricalpunch tool is slidably mounted.
 4. A crimping tool as defined in claim3, including: a. a stop block fixed on said one leg of said fixedretainer block; and, b. a resilient cushion member mounted between saidmovable retainer plate and said retainer block for normally biasing saidmovable retainer plate against the said fixed retainer plate, and toallow said movable retainer plate to be moved perpendicularly away fromthe fixed retainer plate during a punching operation.
 5. A crimping toolas defined in claim 4, including: a. a resilient holding memberoperatively mounted about said second cylindrical punch tool forengagement with the sheets of material to be crimped for holding thesame in place during a punching operation.